Colorectal adenoma explained

Colorectal adenoma
Field:Gastroenterology
Symptoms:Asymptomatic, rectal bleeding
Complications:Colorectal cancer
Diagnosis:Colonoscopy
Treatment:Polypectomy

The colorectal adenoma is a benign glandular tumor of the colon and the rectum. It is a precursor lesion of the colorectal adenocarcinoma (colon cancer).[1] [2] [3] They often manifest as colorectal polyps.

Comparison table

Colorectal adenoma! Type !! Risk of containing malignant cells !! Histopathology definition
Tubular adenoma 2% at 1.5 cm[4] Over 75% of volume has tubular appearance.[5]
Tubulovillous adenoma 20% to 25%[6] 25–75% villous
Villous adenoma15%[7] to 40%Over 75% villous
Sessile serrated adenoma (SSA)[8]
  • Basal dilation of the crypts
  • Basal crypt serration
  • Crypts that run horizontal to the basement membrane (horizontal crypts)
  • Crypt branching.

Tubular adenoma

In contrast to hyperplastic polyps, these display dysplasia.

Tubulovillous adenoma

Tubulovillous adenoma, TVA are considered to have a higher risk of becoming malignant (cancerous) than tubular adenomas.[9]

Villous adenoma

These adenomas may become malignant (cancerous). Villous adenomas have been demonstrated to contain malignant portions in about 15–25% of cases, approaching 40% in those over 4 cm in diameter.[7] Colonic resection may be required for large lesions. These can also lead to secretory diarrhea with large volume liquid stools with few formed elements. They are commonly described as secreting large amounts of mucus, resulting in hypokalaemia in patients. On endoscopy, a "cauliflower' like mass is described due to villi stretching. Being an adenoma, the mass is covered in columnar epithelial cells.

Sessile serrated adenoma

See main article: Sessile serrated adenoma. Sessile serrated adenomas are characterized by (1) basal dilation of the crypts, (2) basal crypt serration, (3) crypts that run horizontal to the basement membrane (horizontal crypts), and (4) crypt branching. The most common of these features is basal dilation of the crypts.

See also

Notes and References

  1. 6384511 . 1984. Hardcastle. J. D.. Early diagnosis of colorectal cancer: A review. Journal of the Royal Society of Medicine. 77. 8. 673–6. Armitage. N. C.. 10.1177/014107688407700812. 1440108.
  2. 1319254. 1992. Schofield. P. F.. ABC of colorectal diseases. Colorectal neoplasia—I: Benign colonic tumours. BMJ (Clinical Research Ed.). 304. 6840. 1498–500. Jones. D. J.. 1882234 . 10.1136/bmj.304.6840.1498.
  3. 11350874. 2001. Srivastava. S. Biomarkers for early detection of colon cancer. Clinical Cancer Research. 7. 5. 1118–26. Verma. M. Henson. D. E..
  4. Web site: Polyps of the Colon and Rectum. Minhhuyen Nguyen. MSD Manual. Last full review/revision June 2019
  5. Book: Bosman, F. T. . WHO classification of tumours of the digestive system . International Agency for Research on Cancer . Lyon . 2010 . 978-92-832-2432-7 . 688585784 .
  6. Amersi. Farin. Agustin. Michelle. Ko. Clifford Y. Colorectal Cancer: Epidemiology, Risk Factors, and Health Services. Clinics in Colon and Rectal Surgery. 18. 3. 2005. 133–140. 1531-0043. 10.1055/s-2005-916274. 20011296. 2780097.
  7. Web site: Villous Adenoma Follow-up. Medscape. Alnoor Ramji. Updated: Oct 24, 2016
  8. 23208018. 2013. Rosty. C. Serrated polyps of the large intestine: Current understanding of diagnosis, pathogenesis, and clinical management. Journal of Gastroenterology. 48. 3. 287–302. Hewett. D. G.. Brown. I. S.. Leggett. B. A.. Whitehall. V. L.. 10.1007/s00535-012-0720-y. 3698429.
  9. Levine JS, Ahnen DJ . Clinical practice. Adenomatous polyps of the colon . N. Engl. J. Med. . 355 . 24 . 2551–7 . December 2006 . 17167138 . 10.1056/NEJMcp063038 .

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